Complete a batch of tasks in one request

Does anyone know how to complete a batch of tasks in one request in Flowable BPMS?
Is there a way to finish multiple tasks at once using Flowable BPMS?
How can I submit multiple tasks in one request using Flowable BPMS?
Is there a way to batch process tasks with Flowable BPMS?
Does anyone have experience with completing a batch of tasks in one request using Flowable BPMS?

Usually submitting multiple tasks in one call points to the problem in the model.
We are using multi-submit implemented by us. I wish to do not allow modelers to use multi-submit.